[O] [PATCH] Add new keyword :coding for #+include directive

[Pierre Téchoueyres]

Hello org's developpers,

I want to propose the attached patch which allow you to specify an
optionnal `:coding' keyword to the `#+INCLUDE:' directive.

This allow you to specify something like
#+begin_example
,#+INCLUDE: "myfile.cmd" src cmd :coding "cp850-dos"
#+end_example
Which allow you to have different encoding for your various sources
files.

This allow me to include localised Microsoft Windows batch sources
inside my utf-8-unix org-files.

Thanks in advance for your remarks.

Pierre